Triumph of the Spirit(1989) [Avram Arouch]: Killed (off-screen) by guards in a concentration camp; we learn of his death afterwards when Willem Dafoe hears about it from other inmates. (Thanks to Binky)

Virtuosity(1995) [John Donovan]: Electrocuted by Russell Crowe in a virtual-reality simulation, causing Costas to die of shock in reality. (Thanks to Binky)

Andromeda: Be All My Sins Remembered(2002) [Bobby Jensen]: Electrocuted when Lisa Ryder touches a live wire to his leg. (Thanks to Binky)

Charmed: Saving Private Leo(2002) [Rick Lang]: Killed in an explosion, along with his brother (Louis Mandylor), when their position is bombed during the battle of Guadalcanal; he and Louis appear as ghosts throughout the episode, and are finally sent back to Hell when Holly Marie Combs casts a spell to get rid of them. (Thanks to David31, Philip, Jonathan, and Binky)

Saw: The Final Chapter (Saw 3D) (2010) [Mark Hoffman]: Presumably dies of starvation after Cary Elwes chains him up in a room, then locks him in after removing the saw so that Costas has no means of escape. (Although this is supposedly the final Saw film, the possibility still remains for Costas to be brought back if another sequel is made.) (Thanks to Tommy)